1) Field of the Invention
The field of this invention is directed to a safety enclosure for a hypodermic needle that has a fore end that assumes an angular position relative to the aft end of the needle.
2) Description of the Prior Art
Within the medical field, more and more patients require the use of vascular access devices as part of their care. Vascular access devices are used on the patients to supply pain drugs, chemotherapy, antibiotics, antiviral or antifungal drugs as well as for hydration and nutrition. In recent years, there has been a substantial increase in the number of patients with implanted ports. An implanted port requires a special needle to be inserted through the skin of the patient and into the port. The most common type of such needle includes a ninety-degree bend. Because of the configuration of the needle, removing the needle at the end of the infusion therapy is particularly dangerous exposing the medical practitioner to a high degree of risk of needlestick injury.
Implanted ports were first introduced in the early 1980's. These vascular access devices are surgically placed under the surface of the skin. The implanted port consists of a catheter and a reservoir. The placement requires a minor surgical procedure with the catheter being threaded into a vein with the reservoir then being placed in a subcutaneous pocket of the body. A common location of such a subcutaneous pocket would be in the anterior upper chest wall below the clavicle. The top of the port, called the septum, is made of a rubber or self-sealing silicon. It is through this part of the port that an infusion needle is inserted for filling the reservoir of the port or aspirating blood or fluid. The septum allows the needle to enter, holds the needle in place, stabilizes the needle during infusion therapy and reseals once the needle is removed.
In order to extend the life of the usage of the septum, damage to the septum is to be minimized even after repeated punctures by a needle. To minimize the damage to the septum, a non-coring needle is preferred. A traditional needle will poke a hole and result in leaks from the septum only after a few punctures prematurely ending the life of the port. A non-coring needle pierces the septum like a knife so that upon removal, the septum can seal itself cleanly. These special non-coring needles are commonly called a Huber needle. Non-coring needles also prevent fragmentation of the septum material (rubber or silicone) that could lead to occlusion of the infusion catheter attached to the port or infusion of fragment(s) into the vein of the patient.
Huber needles are designed in different lengths and different configurations. Straight needles are used for flushing the port, drawing blood or administering bolus injections. Needles bent at a ninety degree right angle are used for longer term infusion therapy. This angle relationship of the needle allows the Huber needle to be more safely anchored to the skin around the port. These needles are commonly left in place for a period of several days. Both straight and right angle Huber needles commonly have "wings" alongside the needle with these wings being used for securing the Huber needle to the patient by taping the wings to the skin of the patient plus facilitating insertion and removal.
Implanted ports have advantages such as reduced risk of infection, no need for a dressing, no need to restrict activities of the patient permitting the patient to normalize their lives. However, the implanted port has one significant disadvantage, and that is there is a high degree of needlestick injury during removal of the Huber needle by the medical practitioner. It is estimated that there are probably in excess of 850,000 needlestick injuries in the medical field each and every year. In conjunction with needlestick injuries, there is a risk of the medical practitioner acquiring a disease such as aids or hepatitis. Although it may be said that it is the carelessness of the medical practitioner that results in a needlestick injury, it has been shown in the past that constructing needles to be safer substantially reduces the number of needlestick injuries eliminating the asking of the medical practitioners to make behavioral changes in the way of handling hypodermic needles. The difficulty of the removal of the needle, rather than carelessness, is what commonly causes needlestick.
The procedure of removing a Huber needle commonly produces what is known as bounce-back which comprises a rebounding effect. Bounce-back is an action which by pulling on the needle or needle attachment, the sharpened end of the needle hooks into the port. This hooking of the needle is due to a snag occurring impeding the removal of the needle from the septum. The medical practitioner thus pulls harder contracting the muscles of his or her arm. When the needle is finally released, the muscles relax and an opposite movement takes place and drives the Huber needle point down into the non-dominant hand of the medical practitioner thus causing the common form of needlestick injury.
Two devices have been on the market to help reduce the risk of needlestick injury. One device consists of a protective device that fits over the port. The nurse then uses a hemostat to pull the needle up into the device for containment during removal of the needle from the patient. The device and the needle is then disposed of. One disadvantage of this device is that it requires a significant change in technique having to do with the removal of a Huber hypodermic needle, and it also requires the use of additional equipment, the hemostat, and its use requires a significant amount of dexterity.
A second device is a scissors-type device formed of two blades which are slid under wings of the needle and against the patient's skin. When the needle is being removed, the bottom blade of the device stabilizes the device while the upper blade pulls out the needle. The needle is held in the blade but the sharp end remains exposed. This device also requires a significant change in technique and has a further disadvantage in that it does not fully contain the sharp end of the needle.
There is also a device called a Huberloc.TM.. Also the Huberloc.TM. device requires a change in technique but it does eliminate pulling a bare needle out of a port. Also, the Huberloc.TM. has the advantage that it does fully contain the sharp end of the needle. Also, the Huberloc.TM. requires the usage of additional equipment which comprises a plastic holder to be used in conjunction with the needle.